I have transgender friends and have been involved in stuff around sexual diversity and gender issues etc for years. So I am worrying that I might be over-sensitive to what is a fairly normal developmental stage.
Basically DS talks about wanting to be a girl when he grows up. Yesterday he was going on quite a lot about whether I would have loved a little girl more than him, would I love him if he was a little girl, etc. (NB I have never said anything to or in front of him about having preferred a girl, because I didn't want a girl rather than a boy; when I was PG I was happy to take what I got).
I know sex isn't entirely binary, and gender is partly a social construct anyway, but I want to do the best for my child ie neither ignore what may be a real problem nor make a big fuss over something that isn't that big a deal.
I suppose one thing that makes me inclined to believe it probably isn't a big deal is, erm, DS' love of his own willy. That suggests to me that he is comfortable in his own body, at least.